In order to achieve an improvement in the comfortability of houses in cold districts and the comfortability of houses in warm districts in the cold season, a floor heating technology for heating the inside of a house from the floor has conventionally been proposed and put into practical use. In the case of a detached house, there is adopted a technology with which, for instance, a heat radiation board (also called the “panel”) for floor heating is incorporated between a sleeper and a floor board or on the upper surface (or on the upper side) of a backing plywood laid on the sleeper, and heating is performed using the heat radiation board. In the case of condominium such as an apartment house, there is adopted a method with which, for instance, a heat radiation board for floor heating is laid directly on the upper surface of a floor slab or on a backing plywood laid on the upper surface of the floor slab.
In JP 60-223922 A, JP 03-175216 A, JP 04-80596 A, JP 08-261485 A, and the like, for instance, there are proposed heat radiation boards for floor heating having a structure where grooves or spaces are formed in one surface of each plate-like member made of a soft foam or a hard foam, fluid tubes (heat carrier flexible tubes) are embedded in the grooves or the spaces, and the surfaces of the tubes are covered with a heat equalizer material such as an aluminum foil.
Generally, these heat radiation boards (panels) that have conventionally been known are obtained by forming grooves or spaces in elongated and narrow plate-shaped members along the lengthwise direction of the plate-like members and embedding fluid tubes, through which a fluid is to be allowed to flow, in the grooves or the spaces. In order to install a heat radiation board having this structure, there is generally adopted a technology with which a wide heat radiation board is assembled in advance at a place other than the installation site and then is brought to the installation site to be installed. With this conventional method, however, there occurs a problem that when the assembled wide heat radiation board is folded, the fluid tubes are buckled or are damaged by friction with the grooves provided in the plate-like members.
The buckling of the heat carrier tubes or the damage due to the friction with the grooves provided in the plate-like members frequently occurs in the end portions of the plate-like members through which the fluid tubes extend from one to the other of adjacent elongated and narrow plate-like members. By focusing attention on this fact, a method of solving the problem has been studied and there has been proposed a heat radiation board having a structure in which the plate-like members are made detachable (see JP 11-141899A, JP 11-294783A, etc.). As a result of further studies conducted, however, there has been found that although the aforementioned problem can be solved, the heat radiation board having the proposed structure still suffers from problems in that the manufacturing process is complicated because the number of plate-like members is increased, the installation is also complicated because it is required to conduct the installation while fitting the fluid tubes in the grooves provided in the plate-like members, and the surface of the heat radiation board after the installation is uneven although a flat surface is desired.